桑叶茶中多酚、黄酮含量与抗氧化作用的相关性研究

Correlation Between the Contents of Active Substances in Mulberry Leaf Tea and Their Antioxidant Activities

研究桑叶茶提取物的活性成分、含量及体外抗氧化作用。采用分光光度法测定桑叶茶中总多酚及总黄酮的含量,并采用超高效液相色谱(UPLC)法测定其6种多酚类成分的含量,通过测定DPPH·和ABTS+·清除率评价不同批次桑叶茶提取液的体外抗氧化活性。结果表明:桑叶茶中总多酚含量为8.12~16.5 mg/g,总黄酮含量为30.54~54.96 mg/g;6种多酚类成分含量为:新绿原酸含量0.30~0.72 mg/g、绿原酸含量2.18~5.06 mg/g、隐绿原酸含量0.77~1.26 mg/g、芦丁含量0.46~2.10 mg/g、异槲皮苷含量0.56~1.59 mg/g、紫云英苷含量0.20~0.67 mg/g;11批桑叶茶均具有清除DPPH·和ABTS+·的作用。相关性分析结果表明,总多酚、总黄酮含量分别与清除DPPH·和ABTS+·自由基活性呈显著正相关(P<0.05);桑叶茶中绿原酸、芦丁和异槲皮苷与其抗氧化能力呈正相关,且DPPH·和ABTS+·清除变量投影值均大于1。试验表明,桑叶茶抗氧化作用的主要成分为绿原酸、芦丁和异槲皮苷,可为桑叶茶的质量标准制定提供参考。

The active components,contents and in vitro antioxidant activities of mulberry leaf tea extract were explored.The content of total polyphenols and total flavonoids in mulberry leaf tea was determined by spectrophotometric method,and the content of its six polyphenolic components was determined by ultra performance liquid chromatography(UPLC).The antioxidant activity of mulberry leaf tea extract was evaluated by scavenging DPPH and ABTs*free radical method.The results showed that the contents of total polyphenols and total flavonoids in the extracts of mulberry leaf tea were 8.12~16.5 mg/g and 30.54~54.96 mg/g respectively.The contents of neochlorogenic acid,chlorogenic acid,cryptochlorogenic acid,rutin,isoquercitrin and astragalin in the extracts of mulberry leaf tea were 0.30~0.72 mg/g,2.18~5.06 mg/g,0.77~1.26 mg/g,0.46~2.10 mg/g,0.56~1.59 mg/g and 0.20~0.67 mg/g respectively.Eleven batches of mulberry leaf tea had the ability to scavenge DPPH and ABTS*free radicals.Correlation analysis showed that total polyphenols and total flavonoids were positive correlated with the activity of scavenging DPPH and ABTS*free radicals(P<0.05).There was positive correlation between chlorogenic acid,rutin,isoquercitrin in mulberry leaf tea and its anti-oxidant ability.The variable projection value was greater than 1.In conclusion,chlorogenic acid,rutin and isoquercitrin are the main material basis for the antioxidant effect of mulberry leaf tea,and provide a favorable reference of the qualitative analysis of mulberry leaf tea.